<?php

$a = 5;//101
$b = 6;//110

$a = $a ^ $b; //011 = 101 ^ 110
$b = $a ^ $b; //101  = 011 ^ 110
$a = $a ^ $b; //110  = 011 ^ 101

echo "a ==> $a" , "\n\n", "b ==> $b","\n\n";
